Insulating plaster-board



G. H. ELLIS.

INSULATING PLASTER BOARD.

APPLICATION FILED DEC. 5.19]!!- Patented Sept. 30, 1919.

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INSULATING PLASTER BOARD.

APPLICATION FILED DEC-5.19M}.

1 ,3 7, 1 58 Patented Sept. 30, 1919.

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GEORGE H. ELLIS, OF ST. PAUL, MINNESOTA.

INSULATING rLAsrEn-nom.

Specification of Letters Patent. Patented Sept. 30,1919.

Application filed December 5, 1918. Serial No. 265.355.

To all whom it may concern:

Be it known that I, Gronen H. ELLIS, a citizen of the United States, residing at St. Paul, in the county of Ramsey and State of Minnesota, have invented certain new and useful Improvements in Insulating Plaster-Board; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it. appertains to make and use the same.

My invention has for its object to provide a low cost and highly efiicient heat insulating lath board; and to such ends, generally stated,the invention consists of the novel construction and arrangement of elements hereinafter described and defined in the claims.

A board or sheet ,material of the above character to be commercially valuable, must not only be of low cost, but should be very efficient as a heat insulation and should be of such construction and character. that plaster applied thereto will be positively held and interlocked therewith, and moreover, should be of a cellular material that will stretch and compress under a force less than that which will crack the plaster. My improved heat insulating lath board meets all of these requirements.

This improved insulating lath board may be commercially made at low cost from various different fibers, such, for example, as cereal straws disintegrated or pulped and preferably reduced to approximately what is known as half stock. However, I have found in practice that this heat insulating lath board may, in point of cheapness of manufacture and efliciency of the produced article, be made from pulped waste paper. Waste paper, as is well known, may be obtained in large quantities at low cost in all parts of most countries and especially of the United States.

In commercial practice, the waste aper may be purchased, the sulfite and etter grades of paper can be sorted out and reused to make high grade paper, and colored paper may be sorted out and the dye stock reclaimed therefrom. I have found that by this practice the salvage obtained will pay for the cost of paper, so that the 7 main bulk of the paper which would be used in making of the insulating lath board, would cost practically nothing. Moreover, waste paper contains sizing which, to a considerable degree, makes water proof the board made therefrom. This waste paper, as stated, is pulped but need not, and preferably is not entirely disintegrated. It is, however, reduced to a pulp of such character that it may be molded or pressed to the desired form with the dovetailed lock grooves formed therein by means of suitable so-called core bars, as will presently appear. The interlocking of the plaster to the board 1s best accomplished by' providing the latter with parallel dove-tailed grooves formed therein for the purpose of giving the board its integral, coherent and self-sustaining form.

- The improved insulating lath board and one of the many possible devices for forming the same is illustrated in the accompanying drawings wherein like characters 1ndica-te like parts throughout the several views. Referring to the drawings:

Figure 1 is a face elevation showing a section of the lath board;

Fig. 2 is an edge elevation thereof, some parts being sectioned;

Fig. 3 is a section on the line 3-3 of Fig. 1;

Fig. 4 is a section on the line 4-4 of Fig. 1, but showing also plaster applied to the board;

Fig. 5 is a plan view of a mold in which the insulating board may be conveniently made; and

Fig. 6 is a transverse sectional view of Fig. 5.

The insulating lath board above described is indicated by the numeral 7 and its dovetailed grooves by the numeral 8. The mold illustrated for making the board comprises a rectangular marginal frame 9 which is open at both top and bottom. For forming the dove-tailed grooves in the board, I provide parallel so-called core bars 10, the upper edges of which are dove-tailed 1n form and the lower edges of which are flanged and mounted to slide in guide bars 11, which, in turn, are supported at the bottom of the box by cross bars 12. The guide bars 11 are provided with laterally spaced ribs 13, the ends of which abut loosely against the sides of the core bars 10. The upper edges of these ribs 13 are below the dove-tailed portions of the bars 10 and.

they serve to support a sectional botttom screen 14.

v The. pulp is poured or placed inthe mold onto the. screen 14 .tailed upper edges the proper depth and then an upper screen therefrom,

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until it covers the do-"veof the core bars 10 to 1@ 1s applied on top of the pulp, and the by means of a press, or otherwise, is tightly as shown, is provided with a marginal frame 16 which, of course, is removable with the said upper screen. After the sheet has been compressed and the surplus water extracted the core bars 10 are withdrawn endwise from the board. The core bars are shown as attached at their outer ends to a common connectin bar 17. K

After the board as been thus formed,

the mold can be turned upside down and the board will then be deposited on the screen 15, which acts as a tray for supporting the board while it is being dried.

After the board has been properly dried, its surface may be impregnated or coated with a water proofing material, such as coal tar indicated by the heavy black linesmarked 18 on Fig. 2 only.

Obviously, a flat surface, even of a fibrous board will not give the required positive interlocking connection between the plaster and the board, and hence, such fibrous board must be provided with dove-tailed grooves or other surfaces that will positively interlock the plaster to the board. The plaster has very little elasticity and is easily cracked, and moreover, the plaster will shrink considerably in drying, will be cracked by any lath board with which'it is positively interlocked unless the lath board be of a material that will stretch and compress under a force'less than that required to crack the plaster. Not only does the plaster shrink in drying, but varying degrees in temperature ofthe plaster will cause such materials as wood to expand and contract under varying degrees of moisture,

and such material as metal will expand and contract under-varying degrees of temperature. Neither wood nor metal, therefore,

compressed. The upper screen 15,.

' may be used .to stretch and compress have been successfully used as a lath board, that is, as a board or sheet proper against which plaster may be applied and positively interlocked therewith without breakin of the plaster under the varying conditions noted. Metal has been unsuccessfully used in the form of expanded lath to be applied on sheathing boards.

My improved insulating lath board, in addition to itsheat insulating quality and its special adaptation to hold plaster without breaking of the latter, performs the function both of sheathing and of lath and on studdin or joist, either lnside or outside of a building without sheathing or wooden boards of any kind. Of course, where additional strength is required, such boards may be used in connection with the lath board, but they are not necessary.

In Fig. 4: plaster 19 is shown as applied to the lath board, and this plaster, in the operation of applyin the same, is formed with integral lock ribs 20 that fill and fit the lock ooves 8, thereby positively interlocking t e plaster to the lath board.

What I claim is:

2. A lath board composed of disintegrated vegetable fiber pulp and formed with depressions to positively interlock with plaster applied thereto, the fiber pulp being adapted under a force less crack said plaster.

my signature than that which will In testimony whereof I aflix in presence of two witnesses.

GEORGE. H. ELLIS. Witnesses HARRY D. KILGORE. F. D. MERCHANT. 

